This invention relates generally to articulated tractors, and more particularly concerns a lighting arrangement for the tires of the tractor.
The trend in today's agricultural industry is to maximize the efficiency of each crop producing unit of land by increasing the size of the units. The larger units minimize the manual labor involved in farming by making it possible to effectively utilize large horsepower tractors and their related implements.
As the horsepower requirements of tractors increases, it becomes more economical and efficient to design, build, and use a tractor that is articulated. The articulated tractors become the preferred type, because the two-wheel-drive and the four-wheel-drive designs can produce the higher tractive efforts required by the higher horsepower of the tractor, without sacrificing the tractor's maneuverability.
To fully capitalize on the benefits of the two and four-wheel-drive articulated tractors, the farmer must be able to operate them twenty four hours a day during the extremely brief, but critical, planting and harvesting seasons. The conventional lights for illuminating the front tires of articulated tractors are secured to the front of the tractor cab. The cab is conventionally positioned on the front section, behind the front axle, with the lights located above and to the rear of the tires, when the tires are set at the standard tread width.
This conventional arrangement is satisfactory when the tractor is being used in the production of non-row crops, e.g. wheat, because the operator does not need to precisely position the tractor tires with respect to the crops. However, the conventional lighting arrangement does not provide adequate illumination of the front tires to allow the operator to steer the tractor through a field of row crops, e.g. corn, soy beans, and sun flowers, after the sun has set, because the operator must precisely position the tires with respect to these crops.
When the conventional articulated tractor is used for row crops operations, the operator's steering ability will be impaired for two reasons. The first reason being the intermittent reflection of light off the tread of the front tires. This reflection produces a strobe light effect that will inhibit the operator's ability to concentrate on the tire/crop positioning, thereby decreasing his steering accuracy.
The second reason for the operator's impaired steering ability is the shadows produced by the tires when they are set at a minimum tread spacing. Under these conditions, the tires cast shadows on their inside surfaces that obscure the operator's view of them. This obscured vision decreases the operator's steering ability by making an accurate positioning of the tires with respect to the crop extremely difficult.
If an attempt was made to improve the operator's nighttime steering ability by relocating the cab on the rear section of the articulated tractor, the cab mounted lights would still not produce adequate illumination for the operator. Although the lights would be further behind the front tires, the above mentioned strobe light effect and narrow tread spacing shadows would still impair the operator's night steering ability.
In addition, the lights being mounted on the rear section would create a new impairment situation, because the lights will move away from the tires when the front section rotates with respect to the rear section during a turn. In this situation, the operator's visibility of the tires will decrease, which will again impair his ability to accurately steer the tractor during nighttime row crop operations.
If another attempt is made to improve the nighttime steering ability of the operator by supplementing the above arrangements with the structure establishing the wheel base lighting in U.S. Pat. No. 1,818,126, the new system would still fail to provide the necessary tire illumination. The addition of the '126 structure still fails to provide a workable system, because it was developed for utilization on a moving automotive or truck type vehicle to provide illumination of the moving vehicle's wheel base for the benefit of the operator of an oncoming vehicle. In achieving its goal, the '126 system positioned a downwardly and rearwardly oriented light in front of and above the vehicle's front axle.
Since the '126 arrangement was not developed to assist the operator of the illuminated vehicle, it is not surprising to find four factors that limit its effectiveness, when its light position and orientation are applied to an articulated tractor. The rearward orientation along produces the first two limiting factors. First, the light will be directly reflected toward the operator off the ground, tires and wheels. This reflection will severely limit the operator's visibility of the inside surface of the tires, thereby diminishing his ability to accurately steer the tractor. Secondly, the light reflecting off the tire treads will again produce the above mentioned steering ability inhibiting strobe light effect.
The next limiting factor of the application of the '126 structure to an articulated tractor is the restriction of the illumination of the '126 light to the rear half of the front tires inner surfaces. With this particular tire illumination, the operator will only know the actual position of the tires with respect to the crop. He will not have the ability to anticipate adjustments in the tires/crop position, because he will not see the crop until it is under the tire and/or the axle. Since the operator cannot anticipate turning adjustments, his ability to accurately steer the tractor will again be diminished.
The last limiting factor of the '126 lighting of an articulated tractor arises from the difference between the axle of an articulated tractor, in particular a four-wheel-drive tractor, and the axle of an automotive or truck type vehicle. The axle of the tractor is much larger than the axle of the '126 type vehicle. With the '126 light positioned in front of and above the tractor's larger axle, a very large shadow will be produced in the already limited illumination pattern. This large shadow will severely limit the operator's visibility of the tire, thereby again diminishing his ability to accurately steer the tractor in night row crop production operations.
In light of the fact that none of the above lighting arrangements give the articulated tractor operator sufficient tire illumination to accurately steer the tractor during nighttime row crop operations, the tractor will destroy the crops during these operations. Since a farmer must be able to use his tractor for both day and night operations without damaging the crops, the benefits of the high horsepower articulated tractors cannot be enjoyed by the farmer since he cannot use a crop-destroying tractor in producing his row crops.
Accordingly, it is an object of the present invention to provide a tire illumination arrangement for an articulated tractor which will make it possible to use the tractor for nighttime row crop operations.
With more particularity, it is an object of the present invention to provide an articulated tractor with a row crop tire illumination arrangement that will not impair the operator's night steering ability by breaking his concentration with a strobe light type reflection off the tread of the tires.
Similarly, it is an object of the present invention to provide a row crop tire illumination arrangement for a tractor that will not diminish the operator's night steering ability by interrupting his view of the front tires with straight reflections of light off the tires, the ground, or the wheels.
Additionally, it is an object of the present invention to provide an articulated tractor with a row crop tire illumination arrangement which has an illumination pattern that is free of limitations or interruptions caused by shadows produced by components of the tractor.
Finally, it is an object of the present invention to provide an articulated tractor row crop tire illumination arrangement that gives the operator the ability to anticipate turns by continuously illuminating the lower front quadrant of the inner surfaces of the front tires.